/*
 * Copyright Camunda Services GmbH and/or licensed to Camunda Services GmbH
 * under one or more contributor license agreements. See the NOTICE file
 * distributed with this work for additional information regarding copyright
 * ownership. Camunda licenses this file to you under the Apache License,
 * Version 2.0; you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
package org.camunda.bpm.engine.impl.tree;

import org.camunda.bpm.engine.impl.pvm.PvmActivity;
import org.camunda.bpm.engine.impl.pvm.process.ActivityImpl;
import org.camunda.bpm.engine.impl.pvm.process.ScopeImpl;

/**
 * Walks the flow scope hierarchy upwards
 *
 * @author Thorben Lindhauer
 */
public class FlowScopeWalker extends SingleReferenceWalker<ScopeImpl> {

  public FlowScopeWalker(ScopeImpl startActivity) {
    super(startActivity);
  }

  protected ScopeImpl nextElement() {
    ScopeImpl currentElement = getCurrentElement();
    if (currentElement != null && ActivityImpl.class.isAssignableFrom(currentElement.getClass())) {
      return ((PvmActivity) currentElement).getFlowScope();

    }
    else {
      return null;
    }
  }

}
